For nearly two hundred years transporting refined materials and raw materials by railcar has been a popular mode of transportation. This mode of transportation continues to be especially popular when transporting cargo to and from ships or when transporting bulk materials from one inland site to another inland site. Numerous types of railcars, including but not limited to, boxcars, refrigerated boxcars, flatcars, tankers, container carriers, gondolas, hoppers, and auto transporter have been designed and used to transport various types of cargo that include refined and raw materials.
One popular railcar for transporting these materials is the carbon black railcar. The carbon black railcar is a specialized hopper car, which is used to transport dry bulk commodities. These commodities include grains, industrial minerals, plastic pellets, crushed rock, gravel, and sand. In general, these cars are loaded with commodities through the top of the railcar and are unloaded through bottom outlet valves (BOVs) on the bottom of the railcar.
These railcars are typically equipped with a BOV and a hatch cover to secure the railcar's cargo and to prevent spillage. In addition, a sanitary cover is typically mounted over the BOV and affixed via valve cover locks and a chain to the railcar. These sanitary covers prevent or reduce contamination of the railcar's cargo either during loading, during transport, or when the railcar is idle but loaded with cargo. However, when not in use, the chains securing the sanitary covers can catch on the tracks. When such occurs, the sanitary cover usually dislodges and is lost.